It is very rare for jewellery to be made with 100% precious metals. Most jewellers alloy precious metals with other metals, to give the piece more durability, to make it easier to work with, and to make it more wearable. However, because of this practice, it is required in some countries to mark jewellery with the percentage of precious metal present. This is called hallmarking, but it’s not required everywhere.
Hallmarking is required by law in the UK. In fact, the UK has some of the strictest hallmarking laws. Every piece of jewellery sold in the UK that is made up of precious metal must be sent to one of four Assay Offices, where government employees will test each piece for the precious metal percentage, and then mark the piece with a hallmark.
Historically, hallmarks in the UK were made by punching the mark into the metal. Today, lasers are also used to etch the mark into the piece. The mark that is made depends on which of the four Assay Offices the piece was sent to, but the presence of the mark indicates that the piece was proven to contain the amount of precious metal that the jeweller advertises.
The possible marks include an anchor for the Assay Office in Birmingham, a castle for Edinburgh, a rose for Sheffield, and a leopard head for London. In addition to this legally required hallmark, jewellery pieces will have a purity mark (which consists of two-digit numbers and the letter k, or three-digit numbers) and a maker’s mark (which could be nearly anything, but is often initials or a logo). Additionally, if a piece of jewellery was made in Britain before 1999, it will have a date stamped into it. This was a legal requirement of all British jewellery until that year.
If the jewellery is made with Fairtrade Gold or Fairmined Gold, it will also have one of those 2 stamps proving the 3rd party certification for the provenance of that gold
In the US, hallmarking is not a legal requirement. Many US jewellery collectors instead look for maker’s marks to assure them that a piece is of high quality. The problem is that maker’s marks are not regulated, so there is no way to connect a maker’s mark to a process that proves a piece is advertised honestly. In fact, in the US, there is no legal requirement to even register a maker’s mark. It is simply up to the maker to add their mark as they wish.
Some US companies that have large markets in the UK, do send their jewelry to UK Assay Offices to be hallmarked, so that they can legally sell their pieces overseas. For US customers who want assurances that a piece is advertised honestly, shopping with a company that follows this practice could be a safer bet than shopping elsewhere. But it’s important to note that there are no legal procedures for checking the quality of jewelry in the US before it is sold.
These differences make the jewellery market in the UK and the US quite different to collectors of high quality jewellery.